Purification and characterization of a recombinant human cripto-1 protein

Cripto-1 (CR-1) is a novel protein that contains a modified EGF-like motif and that does not directly bind to any of the known erb B type-1 receptor tyrosine kinase receptors. To more clearly define the biological effects of CR-1 and to more adequately compare the structure-function relationships of CR-1 with other members of the EGF family of growth factors, we have expressed a modified, full-length recombinant human CR-1 protein (rhCR-1) in E. coli and have devised a procedure for the solubilization, refolding and purification of a biologically active form of this protein. We have generated the mature form of hCR-1 from computer assisted predictions of potential signal peptide cleavage sites. Expression of the modified rhCR-1 protein in E. coli was limited to the inclusion bodies. The rhCR-1 protein was found to be expressed at high levels in bacterial cells when fused to a histidine-tag sequence. Refolding of rhCR-1 was found to be difficult because of the large number of cysteine residues in the protein which results in protein aggregation. By chemically modifying the cysteine residues in the rhCR-1 protein with 3-trimethylammoniopropyl methanethiosulfonate, additional positive charges have been introduced into the protein by this disulfiding reagent. This modification facilitates solubilization of the protein when rhCR-1 is denatured. The solubilized, denatured protein was then purified by CM cation exchange and C4 reverse phase HPLC chromatography and refolded in a redox buffer. The refolded, modified rhCR-1 protein was found to be biologically active by its ability to inhibit beta-casein expression, to stimulate the tyrosine phosphorylation of Shc and the activation of MAPK and by its capacity to facilitate branching growth of mouse mammary epithelial cells in type I collagen gels.

Cripto-1 inhibits beta-casein expression in mammary epithelial cells through a p21ras-and phosphatidylinositol 3'-kinase-dependent pathway

Cripto-1 (CR-1) is a recently discovered protein of the epidermal growth factor family that does not directly activate any of the known erbB type 1 tyrosine kinase receptors. Also, CR-1 stimulates the growth of HC-11 mouse mammary epithelial cells. We found that prior treatment of HC-11 cells with exogenous CR-1 induced a competency response to the lactogenic hormones dexamethasone, insulin, and prolactin (DIP) with respect to the induction of the milk protein beta-casein. In contrast, simultaneous treatment of mouse HC-11 cells with CR-1 in the presence of DIP inhibited beta-casein expression. The inhibitory effects of CR-1 on beta-casein expression in response to DIP were not unique to this mouse mammary epithelial cell line, because beta-casein and whey acidic protein expression in primary mouse mammary explant cultures established from midpregnant mice were also differentially inhibited by several epidermal growth factor-related peptides including CR-1. The mitogenic and differentiation effects of CR-1 are mediated by the binding of CR-1 to a cell surface receptor that is known to activate the ras/raf/mitogen-activated protein kinase (MAPK)/MAPK kinase pathway. The inhibitory response of CR-1 in HC-11 cells on beta-casein expression after treatment with DIP can be attenuated by B581, a peptidomimetic farnesyltransferase inhibitor that blocks p21ras farnesylation and activation, and by the phosphatidylinositol 3'-kinase (PI3k) inhibitor LY 294002 but not by PD 98059, a MAPK kinase inhibitor that blocks MAPK activation. These data suggest that the ability of CR-1 to block lactogenic hormone-induced expression of beta-casein is mediated through a p21ras-dependent, PI3k-mediated pathway. This is further substantiated by the observation that CR-1 is able to stimulate the tyrosine phosphorylation of the p85 PI3k regulatory subunit and to increase the activity of PI3k in HC-11 cells.

Nonsteroidal anti-inflammatory drug induced duodenal web

Duodenal webs represent an unusual cause of intestinal obstruction in adults. These anomalies are generally considered to be congenital in origin and usually present in infancy. However, they occasionally become symptomatic in adulthood. In these cases, because of the delay in symptoms, the etiology of duodenal webs in adults is uncertain. Gastrointestinal webs in adults have also been reported in the small intestine and colon. It is generally accepted that these lesions are an acquired defect related to long term nonsteroidal anti-inflammatory drug (NSAID) use. We report a patient with a history of long term NSAID use who presented with symptoms of gastric outlet obstruction due to the presence of a duodenal web.

Serum levels of copper, zinc, iron and ceruplasmin in oral leukoplakia and squamous cell carcinoma

Trace elements have been extensively studied in recent years to assess whether they have any modifying effects in the etiology of cancer. In the present study serum levels of copper, zinc, ceruloplasmin, total iron and total protein were estimated in 92 patients with oral leukoplakia and squamous cell carcinoma and 45 age and sex matched controls. Copper was significantly increased in oral leukoplakia and cancer in both sexes. The level of zinc decreased significantly only in male patients with leukoplakia and cancer. Copper zinc ratio was found significantly elevated in oral leukoplakia and cancer. A marked increase in serum ceruloplasmin was seen in oral leukoplakia and cancer in both sexes. A significant decrease of serum total iron and proteins were observed only in carcinomas. These findings suggest that reduction in the serum total iron and total protein may be due to malnutrition caused, on its turn, by tumour burden. Serum ceruloplasmin level and copper-zinc ratio demonstrated significant differences in the patients of both sexes from those of controls, while, comparing leukoplakia with cancer, a significant difference is only observed in male patients. Thus, the present study shows that these factors have diagnostic value only in differentiating malignancies from normal and a little value as biomarkers of disease progression. However, the exact mechanism responsible for the alteration of these factors in oral lesions is still not clear and a detailed study on large sample size is therefore needed.

Telomerase activity in premalignant and malignant lesions of human oral mucosa

Recent studies have demonstrated a strong association between carcinogenesis and re-activation of telomerase in various human tumors. In the present study, we have analyzed the telomerase activity in 105 oral mucosal samples, including normal mucosa and premalignant and malignant lesions, by using the telomeric repeat amplification protocol assay. The telomerase activity was detected in normal oral squamous epithelium and in 75% of the oral leukoplakias and oral carcinomas. Although the telomerase activity was observed in normal and hyperplastic squamous epithelium, it showed some relationship with certain clinico-pathological factors in malignant lesions. Telomerase activity was found to have a relationship with the grade of tumor differentiation. Of 34 well-differentiated squamous cell carcinomas, only 10 (30%) exhibited high telomerase activity, whereas in moderately or poorly differentiated squamous cell carcinomas, all seven (100%) tumors displayed high activity. In addition, the level of telomerase activity had an inverse correlation with the treatment response in the early-stage tumors, and the activity differed significantly between the tumors in the following intraoral sites: nonkeratinizing mucosa (buccal mucosa, alveolus, and floor of mouth) and tongue. This preliminary result shows that telomerase activity is present in normal oral squamous epithelium, as it is in normal hematopoietic cells and in carcinomas, and that telomerase activity has a relationship with degree of tumor differentiation and treatment response. Thus, assessing the telomerase activity may be a useful prognostic marker in oral squamous cell carcinomas.

Chemical synthesis, structural modeling, and biological activity of the epidermal growth factor-like domain of human cripto

Cripto, also known as human teratocarcinoma-derived growth factor 1 (TDGF-1), contains a 40 amino acid region with some similarity to the epidermal growth factor (EGF) domain. However, sequence homology is largely restricted to the classical cysteine/glycine motif with only limited similarities in other regions. Significant differences to human EGF include the absence of all seven residues between the two N-terminal half-cystines and a five-residue shorter loop between the third and fourth half-cystines. We examine the hypothesis that, in spite of these differences, cripto can adopt the characteristic EGF-like 1-3, 2-4, 5-6 disulfide bond pattern. A comparative structural model of the growth factor cripto was constructed on the basis of its similarity to EGF, transforming growth factor alpha (TGF-alpha), and the EGF-like domain of human clotting factor IX. The predicted disulfide bridges and disulfide-bridged loops were analyzed and appear viable in the modeled structure. Moreover, to ascertain the importance of disulfide arrangement for cripto bioactivity, two 47-residue peptides were synthesized and then refolded using either a simple oxidative or a controlled sequential refolding protocol. The cripto peptides were tested for their ability to stimulate MAP-kinase activity, for inhibition of beta-casein induction, and for Shc phosphorylation in MDA-MB 453 human mammary carcinoma cells and HC-11 mouse mammary epithelial cells. Data suggest that cripto does adopt the 1-3, 2-4, 5-6 disulfide pattern and thus forms the classical EGF-like fold in spite of the significant deletions within the folding domain. The predicted structure of cripto shows some of the characteristics of both the ErbB1- and ErbB3/ErbB4-binding growth factors.

Cripto enhances the tyrosine phosphorylation of Shc and activates mitogen-activated protein kinase (MAPK) in mammary epithelial cells

Cripto-1 (CR-1), a recently discovered protein of the epidermal growth factor (EGF) family, was found to interact with a high affinity, saturable binding site(s) on HC-11 mouse mammary epithelial cells and on several different human breast cancer cell lines. This receptor exhibits specificity for CR-1, since other EGF-related peptides including EGF, transforming growth factor alpha, heparin-binding EGF-like growth factor, amphiregulin, epiregulin, betacellulin, or heregulin beta1 that bind to either the EGF receptor or to other type 1 receptor tyrosine kinases such as erb B-3 or erb B-4 fail to compete for binding. Conversely, CR-1 was found not to directly bind to or to activate the tyrosine kinases associated with the EGFR, erb B-2, erb B-3, or erb B-4 either alone or in various pairwise combinations which have been ectopically expressed in Ba/F3 mouse pro-B lymphocyte cells. However, exogenous CR-1 could induce an increase in the tyrosine phosphorylation of 185- and 120-kDa proteins and a rapid (within 3-5 min) increase in the tyrosine phosphorylation of the SH2-containing adaptor proteins p66, p52, and p46 Shc in mouse mammary HC-11 epithelial cells and in human MDA-MB-453 and SKBr-3 breast cancer cells. CR-1 was also found to promote an increase in the association of the adaptor Grb2-guanine nucleotide exchange factor-mouse son of sevenless (mSOS) signaling complex with tyrosine-phosphorylated Shc in HC-11 cells. Finally, CR-1 was able to increase p42(erk-2) mitogen-activated protein kinase (MAPK) activity in HC-11 cells within 5-10 min of treatment. These data demonstrate that CR-1 can function through a receptor which activates intracellular components in the ras/raf/MEK/MAPK pathway.

Significance of AgNOR count in differentiating malignant cells from reactive mesothelial cells in serous effusions

OBJECTIVE

To distinguish reactive mesothelial cells from malignant cells in serous effusions using silver staining of nucleolar organizer regions (AgNOR) applied to ethanol-fixed cytologic preparations.

STUDY DESIGN

One hundred aspirated samples of benign and malignant effusions were studied using the one-step silver staining method. Eight cytologically atypical samples were also included in the study.

RESULTS

In malignant cells the mean AgNOR count was 4.72 +/- 0.76 (+/- SD), and the AgNORs were irregular in shape, while in benign mesothelial cells AgNORs were comparatively larger, single dots with a mean count of 1.92 +/- 0.23. Of the cytologically atypical samples, five were in the malignant range. The others were within benign limits. Repeat cytology of the second aspirate confirmed that finding.

CONCLUSION

AgNOR study appears to be clinically useful as an additional diagnostic tool for use in ascitic and pleural fluid samples when the cytologic diagnosis is difficult.

Differential expression of jackfruit-lectin-specific glycoconjugates in metastatic adenocarcinoma and reactive mesothelial cells-a diagnostic aid in effusion cytology

Distinguishing reactive mesothelial cells from adenocarcinoma cells in serous effusions on the basis of morphological criteria alone is often difficult. Interest has therefore been focused on identifying reliable methods to supplement the conventional cytological techniques. Plant lectins have been reported as diagnostic markers for malignant cells. We studied 51 aspirated samples of benign and malignant effusions using horseradish-peroxidase-conjugated jackfruit lectin. No significant difference was observed between the cells of pleural and peritoneal fluids. The reactively proliferated mesothelial cells of benign effusions showed a predominance of mild staining while moderate and intense staining was predominant in malignant effusions. Intense and irregular lectin binding was observed in macrophages irrespective of the cause of effusion. The lectin staining method therefore appears to have some clinical significance as an additional diagnostic aid for use in effusion cytology.

Enhanced expression of heregulin in c-erb B-2 and c-Ha-ras transformed mouse and human mammary epithelial cells

Heregulin beta 1 was found to stimulate the anchorage-dependent, serum-free growth of nontransformed human MCF-10A mammary epithelial cells. Unlike epidermal growth factor, transforming growth factor alpha, or amphiregulin, heregulin beta 1 was also able to induce the anchorage-independent growth of MCF-10A cells. In contrast, the anchorage-independent, serum-free growth of c-Ha-ras or c-erb B-2 transformed MCF-10A cells was unaffected by heregulin beta 1, whereas heregulin beta 1 was able to stimulate the anchorage-independent growth of these cells. c-Ha-ras or c-erb B-2 (c-neu) transformed MCF-10A or mouse NOG-8 mammary epithelial cells express elevated levels of 2.5, 5.0, 6.5, 6.8, and 8.5 kb heregulin mRNA transcripts and/or synthesize cell-associated 25, 29, 50, and 115 kDa isoforms of heregulin. Since the MCF-10A cells and transformants also express c-erb B-3, these data suggest that endogenous heregulin might function as an autocrine growth factor for Ha-ras or erb B-2 transformed mammary epithelial cells.

Ultrastructural analysis of the adjacent epithelium of oral squamous cell carcinoma

Fifteen biopsies of the immediate adjacent epithelium of oral squamous cell carcinoma were examined under light and electron microscopy. Light microscopic examination of one micron thick sections revealed that the majority of lesions (67%) had hyperplastic or mildly dysplastic epithelium while the remaining (33%) had moderate to severe dysplasia. Ultrastructural observations showed that all these lesions had subcellular alterations similar to those seen in frank malignant oral tissue, particularly in the lower half of the epithelium. Important ultrastructural changes observed included bizarre nuclei of basal and lower spinal cells, enlarged and multiple nucleoli, presence of interchromatin and perichromatin granules, loss of desmosomes and marked spongiosis as well as disturbed cellular maturation sequences in the keratinocytes evidenced by abnormal and irregular distribution of maturation markers such as keratohyalin granules and tonofilaments. The present study thus shows the value of electron microscopy in the detection of malignant changes in the adjacent epithelium of oral squamous cell carcinoma.

Lectin histochemistry of oral premalignant and malignant lesions: correlation of JFL and PNA binding pattern with tumour progression

The expression of glycoconjugates specific to Jack fruit lectin (JFL) and peanut agglutinin (PNA) in various clinicopathological stages of tumour progression in the oral mucosa were studied. These included various clinical forms of dysplastic and non-dysplastic oral leucoplakias, carcinomas, normal keratinising (gingiva) and non-keratinising (buccal mucosa) epithelia. It was seen that the binding patterns of PNA and JFL in the epithelial cells of various types of oral lesions were more or less similar. Normal non-keratinising epithelium showed mild membrane staining only in the spinal layers, while normal keratinising epithelium showed a moderate membrane staining and mild cytoplasmic staining in all layers. Moderate membrane and mild cytoplasmic staining were observed in leucoplakias, irrespective of various clinical or histological types. In carcinomas, the intensity of lectin binding was high, particularly in the membrane of differentiated cells. Correlation analysis of the binding pattern of PNA and JFL showed significant correlation in the membrane and cytoplasm of all layers with histological stages of tumour progression. The present study thus showed that PNA and JFL may be used as cytochemical probes in differentiating malignancy from benign lesions of the oral mucosa.

Anaesthetic management of a child with Bartter's syndrome

We report the anaesthetic management of an eight-year-old asthmatic boy with Bartter's syndrome who had bilateral orchidopexy with caudal epidural analgesia. Bartter's syndrome is a rare congenital disorder characterized by hypokalaemic hypochloraemic metabolic alkalosis, hyperaldosteronism, hyperreninaemia and hyperplasia of the juxtaglomerular apparatus of the kidneys. Characteristically, although these patients are normotensive they may be hypovolaemic. They may have unstable baroreceptor responses and show marked resistance to vasopressors. Hence, fluid, acid-base and electrolyte imbalances along with haemodynamic instability pose particular problems in their anaesthetic management. Previous case reports have described the management of these patients with general anaesthesia, our patient had his orchidopexy with caudal epidural analgesia using plain bupivacaine 0.5%. The patient was haemodynamically stable throughout surgery and was comfortable with caudal analgesia as the sole anaesthetic. Hypovalaemia, acid-base status and electrolyte imbalance were treated before instituting caudal epidural analgesia. We present this case report which describes the anaesthetic considerations in the light of the pathophysiology of Bartter's syndrome.

Implications of gynaecological abnormalities in pre-selection criteria for cervical screening: preliminary evaluation of 3602 subjects in south India

Early detection and eradication of cervical cancer and its precursor lesions through organized mass cytological screening programmes have recently gained considerable attention in developing countries. Strategies for both cost saving and effective implementation are however required for mass cervical screening in developing countries. In an early cancer detection programme conducted in South India, we analysed cytological abnormalities in 3602 women and correlated the results with other factors, including age, gynaecological complaints, number of years of married life and parity to see if pre-selection for cytologic screening was possible. Only lower grades of dysplasia were found in asymptomatic women below the age of 40 years. In asymptomatic women, malignancy and higher grades of dysplasia were confined to women with a clinically abnormal cervix only. Univariate analysis also revealed that subjects with a parity of more than 3 and a married life of more than 20 years had a significantly higher number of cytological abnormalities. However, on a multivariate analysis the increased number of marital years was not found to be an independent variable. These results suggest that asymptomatic women below the age of 40 years with a married life of less than 20 years and parity below 3, may be excluded from screening campaigns, and that pre-selection for cytologic screening is possible by introducing a programme of clinical and speculum examination of the cervix.

Hen's teeth and whale's feet: generalized characters and their compatibility

We propose a new model of computation for deriving phylogenetic trees based upon a generalization of qualitative characters. The model we propose is based upon recent experimental research in molecular biology. We show that the general case of determining perfect compatibility of generalized ordered characters is an NP-complete problem, but can be solved in polynomial time for a special case.

Argyrophilic nucleolar organizer regions in the evaluation of tumour progression in the oral mucosa: correlation with tissue pathology

The present study has analysed the numbers of argyrophilic nucleolar organizer regions (AgNOR) in normal tissues and in premalignant and malignant lesions of the oral mucosa in order to assess their potential as a biological marker for tumour progression. On comparison of AgNOR numbers in different lesions, carcinomas showed the highest number (4.65 +/- 0.98) compared to leukoplakias (2.38 +/- 0.47) and normal tissues (1.53 +/- 0.39). Spindle cell carcinomas and poorly differentiated squamous cell carcinomas had higher AgNOR counts than well-differentiated carcinomas. In various clinically different types of oral leukoplakia, the lowest AgNOR counts were observed in homogenous leukoplakia and the highest in speckled leukoplakia. No significant difference in AgNOR number was observed between non-dysplastic and dysplastic leukoplakia, although a significant difference was evident between dysplastic leukoplakia and normal oral mucosa. Correlating the AgNOR count and tumour progression, a significantly high positive correlation coefficient (r = 0.7969, P = 0.0000) was observed.

Scanning electron microscopy of different types of oral leukoplakia: comparison with normal and malignant oral mucosa

The present study analysed surface architecture of normal, premalignant and malignant oral mucosa using scanning electron microscopy to evaluate its role in early diagnosis of potentially malignant oral lesions. The surface ultrastructure of the buccal mucosa in tobacco chewers showed variations from that of non-chewers. Homogenous leukoplakia demonstrated well-defined intercellular junctions and the microrugal surface pattern as seen in normal mucosa. In verrucous leukoplakia, the surface layer consisted of characteristically-shrunken desquamated hyperkeratotic cells. Erosive leukoplakia had a discontinuous superficial layer along with complete loss of intercellular ridges. Speckled leukoplakia also showed marked abnormalities such as thickened irregular protrusions and evidence of a villus-like pattern. These villus-like structures were comparatively prominent in leukoplakia showing dysplasia. Oral carcinoma showed marked altered surface ultrastructure and had a pattern similar to dysplastic lesions. The irregular swollen elongated protrusions with villous-like structures that were observed in carcinoma and dysplastic lesions can, therefore, be considered as surface markers for potentially malignant leukoplakia.

Expression of galactoside-specific endogenous lectins and their ligands in human oral squamous cell carcinoma

Human endogenous lectins have a wide spectrum of biological functions. The present study analyses the expression of beta-galactoside specific and N-acetyl-D-galactosamine specific endogenous lectins in oral squamous cell carcinomas using biotinylated neoglycoproteins. The expression pattern of beta-galactosyl-containing glycoconjugates or ligands of beta-galactoside specific lectins in these tissues was also studied using an endogenous biotinylated lectin, the human 14-kDa lectin. For comparison a galactoside specific plant lectin from mistletoe, Viscum album was also employed. The results demonstrate that oral squamous cell carcinomas mainly express accessible binding sites for lactosylated neoglycoprotein (90%) while few carcinomas expressed mild amount of N-acetyl-D-galactosamine specific binding sites (40%). There was no difference in the binding patterns of these probes between well and less differentiated carcinomas. Expression of these neoglycoprotein binding sites were mostly concentrated in immature basaloid cells, indicating a possible association with cell proliferation. The binding pattern of D-galactosyl specific lectins (human 14-kDa and mistletoe lectins) showed conspicuous differences. This feature emphasizes the caution that needs to be exercised in interpreting the biological significance of results attained using plant lectins on human tissue.

Jack fruit lectin-specific glycoconjugate expression during the progression of cervical intraepithelial neoplasia: a study on exfoliated cells

The expression of glycoconjugates specific to Jack fruit lectin (JFL) was studied in the exfoliated squamous cells of different grades of intraepithelial and invasive neoplasia of the uterine cervix. It was observed that while normal cells showed almost negative binding, the lectin binding percentage of squamous cells significantly increased with increasing atypia of the epithelium. Correlation analysis between different groups revealed that mild lectin binding in cells had a negative correlation and intense binding had a positive correlation with various stages of tumor progression. These results indicate that the number of cells with aberrant expression of glycoconjugates increases as neoplastic transformation advances. The percentage of labeled and unlabeled cells also shows a continuous transition from low to severe grades of cervical intraepithelial neoplasia and invasive carcinomas. The present study therefore shows that JFL may be used as a probe for further elaboration of detection and grading of precancerous and cancerous lesions of the uterine cervix.

Alterations in expression of basement membrane proteins during tumour progression in oral mucosa

Expression of three basement membrane proteins--collagen IV, laminin and fibronectin--was studied in normal, hyperplastic, dysplastic and neoplastic conditions of the oral mucosa using immunohistochemistry. Collagen IV and laminin exhibited similar staining patterns, while fibronectin showed a different pattern of expression. The expression of collagen IV and laminin also demonstrated an inverse correlation between staining intensity, thickness and basement membrane continuity in various stages of tumour progression. In contrast to the continuous and intense staining of basement membrane in normal oral mucosa with collagen IV and laminin antibodies, severe dysplasia and carcinoma exhibited discontinuous, thin and weakly stained basement membrane. The expression of fibronectin showed a direct correlation with extent of tumour progression. In normal mucosa, expression of fibronectin was almost absent, whereas in carcinoma intense expression of fibronectin was evident in the basement membrane and basal cells. These results emphasize the value of basement membrane proteins as biological markers for assessing oral carcinogenesis.

Immunohistochemical localization of epidermal growth-factor and its receptor in normal, premalignant and malignant oral-mucosa

An important growth factor involved in epithelial carcinogenesis is the epidermal growth factor (EGF). The present study analyze the expression pattern of EGF and its receptor (EGFR) in different stages of tumour progression in oral mucosa (normal epithelium, non-dysplastic and dysplastic leukoplakias and carcinomas). Alterations in expression pattern of EGFR was not significant in the various tissues from normal mucosa to malignancy. In all these stages EGFR positivity was confined to the immature basal or basaloid cells. EGF however showed marked alterations in expression in different stages of tumour progression in oral mucosa. Most of the malignant cells were positive for EGF antibodies while, only a few lower layers of cells were stained in normal mucosa and in dysplastic leukoplakia lesions, more number of cells expressed EGF than normal tissue. The present study thus shows the autocrine role of the EGF and EGFR and the possibility of using EGF as a marker for tumour progression in oral mucosa.

Alterations in expression of terminal differentiation markers of keratinocytes during oral carcinogenesis

Expression of cytoskeletal proteins has been shown to be dependent on the differentiation status of the tissue. In the present study, expression of two cytoskeletal proteins normally present in terminally differentiated keratinocytes, namely cytokeratin types 10/11 and involucrin, were studied in different stages of tumour progression in the oral mucosa. Results showed that cytokeratins 10/11 and involucrin strongly correlated with the differentiation status of cells. High expression was observed in non-dysplastic hyperplastic epithelium as compared to normal, dysplastic and neoplastic epithelium. In addition, various grades of dysplasia showed an inverse correlation with expression of these proteins. Statistical analysis of the results also showed a negative correlation between the differentiation of upper spinal cells and the stage of tumour progression. It therefore appears that the proteins studied may be useful as markers for epithelial carcinogenesis.

Ultrastructure of oral squamous cell carcinoma: a comparative analysis of different histological types

Twenty-five oral carcinomas and five normal oral epithelial specimens were studied using light and electron microscopy. All histological types (well differentiated squamous cell carcinoma, moderately differentiated squamous cell carcinoma, poorly differentiated squamous cell carcinoma, verrucous carcinoma and spindle cell carcinoma) were seen in the study sample. In addition, 1 case of carcinoma in situ was also present. The normal oral epithelium consisted of three keratinising types (gingiva) and two non-keratinising types (buccal mucosa). The ultrastructural features of oral carcinomas showed good correlation with the features seen in light microscopy. The differentiation status of the lesions showed a relationship with cell and nuclear size, tonofilament and keratin content as well as few other cellular abnormalities. It was also observed that the fine details revealed by electron microscopy were often a means of explaining the characteristic histopathological features of oral carcinoma.

Co-expression of ras p21 and epidermal growth factor receptor during various stages of tumour progression in oral mucosa

Ras p21 and epidermal growth factor receptor (EGFR) have commonly been implicated in a variety of malignancies. The present study immunohistochemically analysed the relationship between the expression of ras p21 and EGFR in normal, premalignant and malignant lesions of the oral mucosa. Except for normal mucosa, all other lesions showed a more or less similar expression pattern of both ras p21 and EGFR. It was also observed that the expression of both proteins was mostly confined to the basal or basaloid cells of the leucoplakia and carcinoma lesions, respectively. Normal keratinizing type mucosa showed expression of ras p21 and EGFR in the basal and lower spinal cells. However, in non-keratinizing mucosa the expression of ras p21 was totally negative while EGFR was restricted to the basal cells. Statistical analysis revealed a good correlation between the expression of ras p21 and EGFR with the various histological stages of tumour progression. The presence of these proteins in immature dividing cells of premalignant and malignant lesions thus emphasizes their relationship with cell proliferation.

Ultrastructural variations and assessment of malignant transformation risk in oral leukoplakia

Oral cancer is the most common malignancy in India, having a well defined precancerous state, leukoplakia. Various follow-up studies have shown that only 4 to 18% of oral leukoplakia lesions subsequently progress into invasive malignancy over a period of time. This study evaluates the potential of electron microscopy in the early detection of malignant changes in leukoplakia. The study revealed that of the 25 leukoplakia lesions examined, 7 showed changes akin to malignancy. Predominant ultrastructural alterations observed were reduplication and discontinuity of the basal lamina, basal cells with pleomorphic and bizarre nuclei containing perichromatin and interchromatin granules, prominent intercellular spaces and poorly formed desmosomes. Since none of these changes were evident under light microscopy the study demonstrates the value of electron microscopy in evaluating oral carcinogenesis. A long term follow-up of such patients is needed to understand the prognostic implications of these ultrastructural variation and how they can be used as a base line for better light microscopic evaluation.

Excimer-laser-induced spatially variant luminescence in pure-silica core fibers with fluorine-doped silica cladding

Optical fibers with pure silica cores of both low and high water content and fluorine-doped silica claddings were irradiated with 248 nm (KrF) excimer-laser radiation. In addition to the differences in the spectra of luminescent emissions of the respective cores, spatial variance was observed in the luminescence behavior across cross sections of the cores. Photographic evidence of this phenomenon is presented along with the corresponding luminescence spectra. Spectral correlations of the spatial variances are made, and the defects that are responsible for the luminescence are discussed.

Expression of lectin-specific cellular glycoconjugates during oral carcinogenesis

The binding pattern of two lectins, concanavalin A (ConA) and peanut agglutin (PNA), in various phases of tumour progression in the oral epithelium was studied. These included non-dysplastic, dysplastic and neoplastic lesions as well as normal tissue. ConA and PNA showed intense staining in the basement membrane of all types of lesions. Little difference was observed in the staining patterns between different stages of oral carcinogenesis, either with ConA or PNA. ConA showed mild cytoplasmic and membrane staining in all types of lesions while PNA showed moderate to intense staining in both the cytoplasm and membrane of lower-layer cells in all histological groups. The present study therefore shows that these lectins have limited value in the elucidation of oral carcinogenesis and are of insignificant diagnostic value.

Argyrophilic nucleolar organizer regions (AgNORs) in inflammatory pre-malignant and malignant lesions of the uterine cervix

Nuclear organizer regions (NORs) code for ribosomal RNA and are associated with non-histone nucleoproteins, which can be identified by silver staining (AgNORs). AgNORs have been correlated to proliferative activity of tumors and hence may be prognosis-related. The present study evaluates AgNOR counts in inflammatory lesions of the uterine cervix, cervical intra-epithelial neoplasia, and invasive cervical squamous carcinoma. Significant variation in AgNOR counts were observed between the three study groups, with invasive carcinoma showing maximum counts. Further, a highly significant positive correlation was observed between AgNOR counts and tumor progression. These results therefore suggest that AgNOR counts may be of significance in the evaluation of cervical carcinogenesis and could elaborate histopathological diagnosis of cervical lesions.

Immuno-pathological and immunological features of oral precancers

Cancer of the oral cavity and oropharyngeal regions constitute about 30% of all cancers seen in India, with Trivandrum District in southern India having one of the highest incidence. Despite easy accessibility for examination and diagnosis, these tumours still cause high mortality, emphasizing the need for better methods of diagnosis and more importantly prognosis. Most oral carcinomas initially present as premalignant lesions and hence understanding their biology and behaviour is vital to the management and control of the disease. This review presents some of the clinico-pathological, immuno-pathological and immunological aspects of oral precancers.

The immunohistochemistry of solid tumours: potential problems for new laboratories

Immunohistochemistry has become an important tool for tumour typing and has the potential to improve the histopathological diagnosis of neoplasms. However, the large number of publications on the different aspects of the technology are often contradictory. In many instances the immunochemical reactions may not be reproducible and can create problems in the diagnosis of certain tumours. The use of optimal materials and techniques enhance the sensitivity, specificity and reproducibility of these methods. In this article we discuss the common problems of tissue preparation, and antigenic variation, distribution and presentation. However, immunopathological diagnosis has to be accompanied by an in-depth and fundamental understanding of basic immunochemistry and diagnostic immunohistochemistry has to be interpreted in the context of a standard clinical and histopathological examination.

Sensitization potential and reactogenicity of BCG with and without various doses of killed Mycobacterium leprae

A study was conducted in 997 individuals in two villages in south India to find the acceptability and sensitizing effect of the antileprosy combination vaccine of BCG plus killed Mycobacterium leprae (KML). Three preparations of the combination, BCG 0.1 mg + 6 x 10(8) KML (I), BCG 0.1 mg + 5 x 10(7) KML (II), and BCG 0.1 mg + 5 x 10(6) KML (III), along with BCG 0.1 mg (IV), and normal saline (V), were used in the study. Each individual received one of the above five preparations by random allocation. They were also tested with Rees' M. leprae soluble skin-test antigen (MLSA) and lepromin-A, both at intake and 12 weeks after vaccination. Reactions to Rees' MLSA were measured after 48 hr; those to lepromin-A after 48 hr and 3 weeks. The character and size of the local response at the vaccination site were recorded at 3, 8, 12, 15, and 27 weeks after vaccination. The mean sizes of postvaccination sensitization to both Rees' MLSA and lepromin-A in the vaccine groups were significantly larger than those in the normal saline group, clearly demonstrating the ability of the vaccines to induce sensitization as measured by responses to the two skin tests. The sensitizing effect was the highest following vaccination with vaccine I. It was not significantly different for vaccines II, III, and IV, although, generally, a dose-response effect was observed. The sensitizing effect attributable to the vaccine was more clearly seen in children than in adults. The above conclusions were the same irrespective of which results were considered, reactions to Rees' MLSA or Fernandez or Mitsuda reactions to lepromin-A. A significant finding of the study was that at intake the Mitsuda reactions provided a measure of sensitizing effect due to vaccine. The healing of vaccination lesions was uneventful. In more than 90% of vaccinated individuals, the lesions had healed by the 12th week in vaccine groups II, III, and IV, and by the 15th week in vaccine group I. The results showed that vaccination with BCG or combination vaccines was equally safe in individuals with or without previous BCG scars. Thirteen persons, aged 10 years or older, developed suppurative lymphadenitis around the 8th week (7 in vaccine group I, 3 each in vaccine groups II and III). However, healing was prompt after drainage in these individuals.

Interferon and interleukin-2 induced spontaneous cell-mediated cytotoxicity: a preliminary evaluation

The contribution of natural cell-mediated cytotoxicity and its modulation with biological response modifiers in antitumour immunity was evaluated in patients with precancers and cancers of the oral cavity. The results were compared to those in normal controls. Both groups of patients showed highly significant depression of the natural killer cell activity. This depression was stage-related, suggesting an influence of tumour or tumour products on this activity. Depression in augmentation of this cytotoxicity was evident in both patient groups with cancers and precancers, suggesting a defect in the response of killer cells to biological response modifiers for reasons other than the tumour per se.

Effect of skin test with M. leprae soluble antigen on reaction to a subsequent test with the same antigen

Soluble skin-test antigens (STA), produced from armadillo-derived Mycobacterium leprae by Drs. Rees and Convit, were expected to meet the long-felt need of a test for leprosy infection and also to serve as tests for measuring postvaccination sensitization induced by vaccine preparations against leprosy. The present paper reports results from two studies examining the influence, if any, of skin testing with Rees' STA on reaction to a subsequent test with the same antigen. In the first study, 2168 persons from households of leprosy patients and from neighboring households were skin tested with Rees' STA twice at an interval of 6 months. In the second study, 1700 persons, free from leprosy, received either Rees' STA or normal saline by random allocation. A random subset of 850 persons was tested with Rees' STA after 3 months. The remaining 850 persons were tested with Rees' STA after 6 months. In addition, 242 leprosy patients were given Rees' STA or normal saline by random allocation, and all of these patients were tested with Rees' STA after 6 months. The results of the two studies showed that among persons reacting with a small size of reaction to Rees' STA, the size of the reaction to the repeat test was significantly larger. However, from the results of the second study, which included a control group, it was clearly seen that the quantum of boosting or sensitizing effect of the first test as well as that of new sensitization was small over a period of 3-6 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Interferon activation of latent natural killer cells and alteration in kinetics of target cell lysis: clinical implications for oral precancerous lesions

Reduced natural killer cell activity was observed in patients with oral leukoplakia and submucous fibrosis compared with normal control subjects. However, the number of target binding lymphocytes was found to be normal in these precancers. Treatment of effector cells with interferon-alpha resulted in highly elevated active killer cell activity, although no change was observed in target binding lymphocyte counts. This finding could imply that precytotoxic cells that are activated by interferon exist in peripheral blood or that direct recruitment of a new cell population takes place. In addition, altered target lysis kinetics was observed, with interferon-activated killer cells demonstrating a tremendous lytic activation that is completed so quickly that a statistical kinetic analysis could not be accurately done. Because natural killer cell activity is an important effector system in immunosurveillance against tumors, its modulation with interferon may be an exciting clinical possibility in the control of malignant transformation or oral precancers.